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Date:   Thu, 25 Jan 2018 23:30:43 +0100
From:   Jiri Benc <jbenc@redhat.com>
To:     Nicolas Dichtel <nicolas.dichtel@6wind.com>
Cc:     Christian Brauner <christianvanbrauner@gmail.com>,
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        linux-kernel@vger.kernel.org, w.bumiller@proxmox.com,
        Christian Brauner <christian.brauner@ubuntu.com>
Subject: Re: [PATCH net-next 0/3 V1] rtnetlink: enable IFLA_IF_NETNSID for
 RTM_{DEL,SET}LINK
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On Thu, 25 Jan 2018 15:20:59 +0100, Nicolas Dichtel wrote:
> Hmm, I don't agree. For me, it would be the correct answer. If user has a socket
> in ns_a and targets a RTM_GETLINK in ns_b, the answer he gets should be like if
> it was done in ns_b.

But that information would be useless for the caller. Why return a
value that has no meaning for the caller and can not be used? More so
when the kernel is aware of what the correct meaningful value is?

> This is already the case with messages received with NETLINK_LISTEN_ALL_NSID,
> there is no reason to do something different.

NETLINK_LISTEN_ALL_NSID is tough due to way it is implemented. But yes,
it should translate the netnsids to be valid in the socket's netns.
That's the only sane way for the listener.

 Jiri